Tom you can use a 4to1 usb splitter, I don't think a mic and a mouse will overload the port. And they're like $5 on amazon, or @ Wallyworld.Tom I don't like having to be "this guy" but a mic will soon be MANDATORY to participate. Things just don't go as well when folks are not able to respond immediately to situations on the track. What went down with you in the VTCC is proof of that.
Get a mic!